A conventional method and apparatus for fault recognition in an internal combustion engine in the region of the high-pressure circuit in the case of a common rail system are described in U.S. Pat. No. 5,241,933. In this method and apparatus, the pressure in the rail is regulated. If the manipulated variable of the pressure regulation circuit lies outside a definable range, the apparatus recognizes a fault.
A disadvantage with this arrangement is that a fault is recognized only in the case of a considerable pressure drop.
A method and device for fault recognition in an internal combustion engine are also described in German Patent Application No. 38 03 078. With this conventional method and apparatus, when the engine is coasting, the actuator which determines the quantity of fuel to be injected is moved to its mechanical stop at which no injection occurs. If, in this operating state, pulses occur at a so-called needle movement sensor, a fault is assumed to exist.
A device for controlling boost pressure in an internal combustion engine operated with turbocharging is described in German Patent Application No. 31 29 686.
One of the objects of the present invention is to be able to recognize faults as reliably as possible using an apparatus for fault recognition in an internal combustion engine.